The field of the invention is elevator cable hangers.
The different types of cables are normally found in the hoistways of elevator systems. The function of the hoist rope, which is attached between the top of the elevator car and the counterweight, is to raise and lower the elevator car. The function of the compensating cable, which is attached between the bottom of the elevator car and the bottom of the counterweight, is to counterbalance the weight of the hoist rope. The traveling cable, also sometimes called lighting or control cable, is a cable which has transmission media for supplying electricity to the elevator car, transmitting signals from the elevator car to the controller for the proper selection of floors, and to supply heating or the like to the elevator car.
Elevator cable hangers are used to attach traveling cable to the elevator car, which is the attachment point for one end of the traveling cable, and the attachment point for the other end of the traveling cable, the other end referred to herein as the motor room end.
The older practice has been to secure the cable hanger on the motor room end of the traveling cable immediately below a junction box in the mid-point of the elevator hoistway. A metal trough is used as a duct for electrical conduit between the junction box and the controller, which is contained in the motor room over the hoistway. A more recent method is to attach the motor room end of the elevator cable hanger at the top of the hoistway; this method is called a motor room attachment or a "home run" attachment. In this case, no junction box is used and the metal trough can be very short. In either case, some sort of hanger must be used to secure the motor room end of the traveling cable.
There are several methods of attaching traveling cables at the elevator car, hoistway junction box, or the motor room. Three standard methods include steel core hanging devices, steel support wire clamps, and wire mesh grips.
When a steel core hanging device is used, a strength member hanger is used to secure a central strength member, normally a wire rope, of a traveling cable. The strength member support is mounted at the top of a bracket, which is bolted to a structural member or other secure location in the hoistway or on the elevator car. The rest of the traveling cable is suspended from the strength member hanger. Prior art has been for the installer to provide a block of wood and carve out an indentation more or less corresponding to the shape of the cable outer jacket. A metal clamp is then placed over the cable and attached by screws or the like to the wood block. Sometimes another block of wood is carved out and used in conjunction with the first wood block to secure the traveling cable.
Although the use of wood blocks secures one end of the traveling cable from excessive swaying during movement of the elevator car, the rough carved wood blocks often cause excessive chafing and wear to the traveling cable outer jacket. It is also found that if the clamping device is too loose, the traveling cable is allowed to rotate, which also causes premature wear to the traveling cable. On the other hand, if the bracket is secured too tightly, the traveling cable is unduly compressed and damage may result to the copper wires or other communication elements in the cable.